Portable reflecting galvanometer



(No Model.)

3Sheets-Sheet 1. O. P. FREY.

PORTABLE REPLEGTING GALVANOMETER.

Patented Oct. 21, 1890.

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3 SheetsSheet 2.

(No Model.)

. O. P. FREY.

. PORTABLE RBFLEOTING GALVANOMETBR.- No. 438,882. Patented Oct. 21, 1890.

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G. P. FRBY.- PORTABLE REFLEGTING GALVANOMETER.

No. 438,882. Patented Oct. 21, 1890.

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ATENT Prion.

CHARLES P. FREY, OF EAST GREENBUSH, NEW YORK.

PORTABLE REFLECTING GALVANOIVIETER.

SPECIFICATION forming part of Letters Patent 1 l'o. 438,882, dated October 21, 1890.

Application filed December 26 1889. Serial No. 334,969. (No model.)

T0 aZZ whom it may concern:

Be it known that I, CHARLEs P. FREY, of East Greenbush, county of Rensselaer, State of New York, a citizen of the United States, have invented certain new and useful Improvements in Portable Reflecting Galvanometers, of which the following is a full, clear, and exact description, reference beinghad to the accompanying drawings, forming part of this specification.

My invention relates to portable reflecting galvanometers; and it consists in an instrument of the class stated in which the frame containing the coils and their terminals and the combined pendent magnet and mirror, usuallycalled the system, are combined with a main supporting-frame by means of devices constituting a universal joint, so that the pendent system-frame may automatically assume a Vertical position in the main supporting-frame.

My invention further consists in devices hereinafter described, combined with the said pendent frame, whereby the center of gravity of the said pendent frame may be varied and adjusted, as and for the purpose hereinafter set forth.

My invention also consists in the combina tion, with the pendent system-frame, of the locking-bolt hereinafter specified, whereby the pendent frame is held firmly to its supporting-frame and prevented from oscillating, and at the same time the mirror, magnets, and attachments constituting the system are sustained and relieved of all strain upon their suspending fiber when the instrument is not in use, as hereinafter set forth.

Figure 1 is afront elevation of a reflecting galvanomet-er containing myinvention. Fig. 2 is a vertical section of the instrument on the line 0000, Fig. 3. Fig. 3 is a similar section of the same on the line y y, Fig. 1, and hence at right angles to the section in Fig. 3. Fig. 4 is a plan in detail of one of the gravity adjusting weights or cups. Fig. 5 is a plan of the hereinafterdescribed universal joint, taken partly in section on the line z .2, Fig. 1; and Fig. 6 is an elevation of the key I preferably employ to operate the hereinafter-described locking-bolt.

A is a frame, which holds or contains the devices constituting what is known as the pendent frame-namely, the coils Btwo of the terminals of which are connected together in series or multiple, the other two terminals being fastened to the binding-posts Z), which are insulated from the frame A, together with the devices constitutingthe system, suspended by a fiber or fibers c in the coils, as shown, showing through th lens-opening a in the frame. These parts, generally speaking, constituting the field and magnet, are well known and common to instruments of this class and do not need detailed description as to their functions and operations.

A standard D and posts D rising therefrom constitute the main or supporting frame of the instrument.

In carrying out one feature of my invention I suspend the frame A' in the main frame by a universal joint, so that the frame A is free to swing or oscillate at its point or points of suspension in any direction in the main frame. In constituting the universal joint I prefer to pivotally hang the frame A in a ring D by means of conical-ended screws d, which are seated in the ring D and enter corresponding recesses on diametrically-opposite sides of the frame-head A, as shown. The adjustment of the bearing-points of the screws d to their recesses in the frame-head is controlled by suitable lock-nuts d, as shown. The ring D is in turn hung to a yoke-piece D supported by and uniting the posts D by means of conical-ended screws (1 seated in said yoke, as shown, and furnished with controlling lock-nuts (Z said screws entering corresponding recesses in the ring D which are diametrically opposite to each other, and which, with their screws d are located at right angles to the pivotal screws d, which suspend the frame A to the ring D A universal joint for the suspension of the frame A to the frame D D is thus constituted, whereby the frame A is free to level itself by assuming a true vertical position, regardless of the frame D D. By this means the necessity of leveling the main supporting-frame of instruments of this class is wholly avoided, and the pendent frame automatically assumes a vertical position when the instrument is placed in any given spot for use.

I prefer to employ the described devices to constitute the said universal joint, but any other and equivalent devices-such, for example, as a ball-and-socket jointmay be used for this purpose.

At E, I show disks or cups composed of or containing areas or portions of different specific gravities. I prefer to construct these disks of metal, as of brass, and to form in them a cup-like recess 6, extending desirably throughout half their area, as shown, which recesses are filled with aheavier metal-such as lead-as shown at c, Fig. 4. These disks thus formed are suspended to the frame A, preferably at its lower end, by means of asleeve 6 which is screw-seated at e to the frame A, and to which sleeve they are adjustably clamped by a nut 6 working on the sleeve and holding the disks to a flange e on the sleeve, as shown. The function of these disks is as follows: When from any cause, such as an unequal distribution of the weight of its working parts or imperfect balancing or centering, the pendent frame is out of plumb, its true equilibrium may be restored and it may be brought to its best position for use in its supporting main frame by adjusting one or both of the disks E by partially revolving them on the sleeve c and thus throwing more or less of their heavier portions to one side or the other of the pendent frame A.

The system and its means of suspension have novel features. The mirror 0 is constructed with a series of small bars of suitably-tempered and strongly-magnetized steel secured to its back or rearward face, as shown at c, and thus formed is mounted on a stem 0 of aluminium or other such suitable metal, while above and below the mirror are flanges c on the said stem and preferably of the same metal as the stem. The stem is united,

as at 0 to its suspending fiber c, which in turn is hung to a pin 0 which is longitudinally adjustable in ahollow nut a, screwseated in the upper end of the frame A, as shown. By means of the pin 0 and nut c the mirror may be adjusted at the center of the magnet-coil. The suspending fiber 0 passes to the center of the coils by an aperture o in the frame A and coils, as shown. A pointer c is fastened to the stem 0 of the mirror at right angles to the plane of the mirror, said pointer being formed, preferably, of aluminium, and by means of a scale a, which may be placed on the lens a in the lens-opening a in front of the mirror, traversed by the pointer, direct readings may be taken by noting the oscillations of the pointer over said scale.

when very delicate observations are desired, it is obvious that the usual lamp-stand and scale or reading-telescope may be employed in the customary manner in connection with. the galvanometer.

F is a disk, which preferably has the upwardly-turned flange 1'", making it thus cupshaped, as shown, and located immediately below and adapted to receive the under flange 0 on the mirror-stem. The diskF is supported by a stem f, which has longitudinal play in the sleeve e as shown.

F is a bolt having play in a suitable slot or recess f in the base I), and adapted to enter the lower end of the sleeve e and fit therein, and also to bear against the lower end of the stem f of disk F in said sleeve. The bolt is preferably actuated by an anglearm f 3 fixed on the bolt, which arm is engaged by a crank-arm f by means of a pin or stud f 5 therein, which works in a mortise f in sald an gle-arm, as shown, the quarter-revolutlon of the crank-arm operating to shoot the bolt in to or withdraw it from the sleeve e The crankarm is desirably operated by a key-such as shown in Fig. 6-which fits to an arbor ff, carried by the. crank-arm. The bolt F is preferably recessed inwardly from its upper end, as at f, and provided with a sprmgf", seated and having play in said recess. Then the bolt F is shot into the sleeve 6 it obviously operates to hold the frame A rig dly to the frame D D, preventing the oscillation of the former on its suspending-joint, and at the same time the bolt F acts to lift the stem f, and thus carry the disk F to and against the under flange 0 on the mirror-stem, thereby lifting the system and carrying its upper flange 0 against the mouth of aperture 0 and relaxing all strain on the fiber c. The tension of the spring f against which the stem f bears when the bolt is shot, as described, is desirably so adjusted asto sustain the weight of the disk F and its stem and the mirror without jar upon the mirror and its suspending fiber, and so that the mirror will be elevated but slightly from its usual position with the system. The upper flange c 011 the mirrorstem acts to prevent the mirror and its stem from being unduly raised by engaging against the mouth or lower end of the aperture 0 By means of the described bolt F, whenthe instrument is not in use the pendent frame A may be rigidly held to the main frame, as set forth, and the mirror and its attached part-s be relieved of all strain.

The instrument is made ready for use by simply withdrawing the bolt F from the sleeve e whereupon the system at once assumes its normal position in the coils, and the pondent frame automatically assumes a true vertical position on its suspending universal joint.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a reflecting galvanometer, the combination, with the frame carrying the magnetcoils and suspended mirror and magnet, and a main frame or support, of a universal joint connecting the two frames and by which the former is suspended to the latter, substantially as and for the purpose set forth.

2. In a reflecting galvanometer, the combination, with the frame A and the frame D D, of a ring Dihaving trunnion-screws d taking into the head A of the frame A on diametrically-opposite sides thereof, and trunnionscrews d seated in the frame D and taking into the ring D on diametrically-opposite sides thereof and at right angles to the trunnion-screws 01, substantially as and for the purpose set forth.

3. In a reflecting galvanometer, the combination, with the suspensory-frame A, containing the coils and suspended mirror, of disks E, having portions or areas of different specific gravities pivotally attached to said frame A, and thereby radially adjustable on their pivot thereon, substantially as and for the purpose set forth.

4. In a reflecting galvanometer, the combination, with the suspensory frame A, containing the coils and suspended system, of disks E, having portions or areas of diiferent specific gravities, a sleeve or hub 6 carried by the frame A, and on which said disks are axially mounted, a holding-flange e 011 the sleeve, and a clamping-nut e substantially as and for the purpose set forth.

5. In a reflecting galvanometer, the co1nbination, with the mirror C, of the stem 0 and the flanges c thereon, above and below the mirror, together with the pointer c on said stem, and its scale, the fiber c, by which said stem is suspended, and the pin and nut 0 substantially as and for the purpose set forth.

6. In a reflecting galvanometer, the combination, with the suspensory frame A, containing the coils and suspended mirror, and the frame D D, furnishing the main support, of a bolt F, having play in the base D of the main frame, and a recess or sleeve 6 on the frame A, into which said bolt takes when shot, substantially as and for the purpose set forth.

7. In a reflecting galvanometer, the combination, with the suspensory frame A, containing the coils and suspended system, provided with stem-flanges c of the disk F, having a stem f, which is seated and has longiseated and having longitudinal play in the wall of said suspensory frame, together with amainframeDD',andaboltF',workingin the standard D, and adapted to be shot into the recessed aperture in said suspensory frame, in which said stem f has play, and to therein engage said stem, substantially as and for the purpose set forth.

9. In a reflecting galvanometer, the combination, with the bolt F, working in the standard D of the main frame and adapted to be shot into an aperture in the suspensory frame A, of an ang1e-armf fixed on said bolt, provided with mortise f and a crank-arm f having a pin f engaging said mortise in said bolt-arm, and provided with a key-arbor f substantially as and for the purpose set forth.

10. In a galvanometer in which the system is suspended by a fiber, and is adapted to be lifted to relax the strain on said suspending fiber, the combination, with said system, of a yielding or elastic lifting device adapted to lift and hold the system in a rigid position and at the same time to yield to the weight of the system, so that the liability to crush or otherwise injure the system when the same is lifted is avoided, substantially as and for the purpose set forth.

CHARLES P. FREY.

Witnesses:

BENJ. F. ALLEN, JOSEPH ROBISON. 

